Lipid lowering effect of S-methyl cysteine sulfoxide from Allium cepa Linn in high cholesterol diet fed rats

The lipid lowering action of S-methyl cysteine sulfoxide (SMCS) isolated from Allium cepa Linn (family: Liliaceae) was investigated in Sprague–Dawley rats fed on 1% cholesterol diet, in comparison to the hypolipidemic drug gugulipid. Administration of SMCS at a dose of 200 mg/kg body weight for 45 days ameliorated the hyperlipidemic condition. The lipid profile in serum and tissues showed that concentrations of cholesterol, triglyceride and phospholipids were significantly reduced when compared to their untreated counterparts. The total lipoprotein lipase activity in the adipose tissue was decreased with also a decrease in the free fatty acid levels in serum and tissues. The activities of the lipogenic enzymes glucose 6-phosphate dehydrogenase and malic enzyme as also of HMG CoA reductase in the tissues remained low on treatment indicating that both the drugs did not favor lipogenesis and cholesterogenesis in the hyperlipidemic animals. The fecal excretion of bile acids and sterols was further increased upon treatment with the drugs. The results are directive to that both gugulipid and SMCS cause reduction of endogenous lipogenesis, increase catabolism of lipids and subsequent excretion of metabolic by-products through the intestinal tract. However, gugulipid is a better drug than SMCS at a low dose of 50 mg/kg body weight.